A method of detecting sub-surface voids in a sample comprises positioning a probe adjacent to a first point on the sample, emitting an ultrasonic wave from the probe towards the sample, moving the probe towards the sample, measuring a shear force amplitude of a reflection of the ultrasonic wave at the probe as the probe moves towards the sample, creating an approach curve by plotting the measured shear force amplitude of the reflection of the ultrasonic wave as a function of a distance between the probe and the sample, and determining whether a sub-surface void exists at the first point on the sample based on a slope of the approach curve.

The present document relates to a heterodyne scanning probe microscopy (SPM) method for subsurface imaging, and includes: applying, using a transducer, an acoustic input signal to the sample, wherein the acoustic input signal has a frequency of at least 1 gigahertz; sensing an acoustic output signal using a probe, the probe including a cantilever and a probe tip, wherein the probe tip is in contact with the surface, wherein the acoustic output signal is representative of acoustic waves responsive to the acoustic input signal that are measurable at the surface; wherein the acoustic input signal is applied to the sample comprising a distinct pulse of acoustic energy followed by a relaxation period, wherein an acoustic power of the acoustic input signal during the pulse is at least twice as large as an acoustic power during the relaxation period. The present document further relates to a scanning probe microscopy method.

Methods and systems for subsurface imaging of nanostructures buried inside a plate shaped substrate are provided. An ultrasonic generator at a side face of the substrate is used to couple ultrasound waves (W) into an interior of the substrate. The interior has or forms a waveguide for propagating the ultrasound waves (W) in a direction (X) along a length of the substrate transverse to the side face. The nanostructures are imaged using an AFM tip to measure an effect (E) at the top surface caused by direct or indirect interaction of the ultrasound waves (W) with the buried nanostructures.

A method of evaluating a thickness of a film on a substrate includes detecting atomic force responses of the film to exposure of electromagnetic radiation in the infrared portion of the electromagnetic spectrum. The use of atomic force microscopy to evaluate thicknesses of thin films avoids underlayer noise commonly encountered when optical metrology techniques are utilized to evaluate film thicknesses. Such underlayer noise adversely impacts the accuracy of the thickness evaluation.

A method of evaluating a thickness of a film on a substrate includes detecting atomic force responses of the film to exposure of electromagnetic radiation in the infrared portion of the electromagnetic spectrum. The use of atomic force microscopy to evaluate thicknesses of thin films avoids underlayer noise commonly encountered when optical metrology techniques are utilized to evaluate film thicknesses. Such underlayer noise adversely impacts the accuracy of the thickness evaluation.

System and Methods may be provided for performing chemical spectroscopy on samples from the scale of nanometers with surface sensitivity even on very thick sample. In the method, a signal indicative of infrared absorption of the surface layer is constructed by illuminating the surface layer with a beam of infrared radiation and measuring a probe response comprising at least one of a resonance frequency shift and a phase shift of a resonance of a probe in response to infrared radiation absorbed by the surface layer.

System and Methods may be provided for performing chemical spectroscopy on samples from the scale of nanometers with surface sensitivity even on very thick sample. In the method, a signal indicative of infrared absorption of the surface layer is constructed by illuminating the surface layer with a beam of infrared radiation and measuring a probe response comprising at least one of a resonance frequency shift and a phase shift of a resonance of a probe in response to infrared radiation absorbed by the surface layer.

A method for obtaining optical spectroscopic information about a sub-micron region of a sample with quantitatively controlled depth/volume of the sample subsurface using a scanning probe microscope. With controlled probing depth/volume, the method can separate top surface data from subsurface optical/chemical information. The method can also be applied in liquid suitable for studying biological and chemical samples in their native aqueous environments, as opposed to air. In the method, a depth-controlled spectrum of the surface layer is constructed by illuminating the sample with a beam of infrared radiation and measuring a probe response using at least one of the resonant frequencies of the probe. The surface sensitivity is obtained by limiting the heat diffusion effect of the subsurface so as to confine the signal. The signal confinement is achieved through non-linearity of the acoustic wave with probe, as well as benefits gained by a high modulation frequency of the infrared radiation source at >1 MHz.

A system for measuring the absorption of a laser radiation by a sample is provided. The system comprises: •(i) a pulsed laser source, suitable for emitting pulses at a repetition frequency f.sub.1 and arranged so as to illuminate the sample; •(ii) an AFM probe arranged so as to be able to be placed in contact with the region of the surface of the sample on one side, the AFM probe having a mechanical resonance mode at a frequency f.sub.m; and •(iii) a detector configured to measure the amplitude of the oscillations of the AFM probe resulting from the absorption of the laser radiation by the region of the surface of the sample, characterized in that it also comprises a translation system designed to displace the sample at a frequency f.sub.p.

The present invention relates to a method for measuring, by a measurement device, characteristics of a surface of an object to be measured. The method includes an approach step of positioning the tip to come into contact with a specific position of the surface of the object to be measured and a lift step of separating the contacted tip from the surface of the object are repeatedly performed with respect to a plurality of positions of the surface of the object. The tip is controlled to vibrate in a portion or the entirety of the approach step and the lift step, and a movement characteristic of the tip is controlled according to a change of the vibration characteristic of the tip.